Mighty River Power is "unlikely" to build a large new power station in the next three to five years because of weak electricity demand, after completing its latest $475 million geothermal station.

Yesterday, MRP's 82 megawatt Ngatamariki power station near Taupo came into official production, and it will be a key factor in lifting the company's 2014 financial year operating profit by an expected 27 per cent.

MRP had already secured a 12 per cent increase in commercial electricity volumes ahead of Ngatamariki coming on line.

But yesterday it said that other big projects were effectively on the back burner.

"We don't see a major development happening in the next three to five years because of the relative overcapacity in the market today," chief executive Doug Heffernan said.

If water storage was above average, there was overcapacity. At present lake levels are almost spot on long-term averages after falling well below during the summer drought.

"Thermal [gas fired] plants are running a lot less than they were five years ago, from way over 50 per cent to way under 30 per cent [nationally]. That's the big impact," Heffernan said.

But the wind power projects were not totally ruled out.

"You need projects ready to build, ahead of the conditions that require them to be built. You need to be prepared so you have projects that are ‘shovel ready'."

That meant it would be only a couple of years from "turning the spade" to getting power to the grid, if new stations were needed.

It was possible some smaller geothermal investments could be made ahead of wind projects.

But MRP wanted options in both wind and geothermal.

In late June, the partly state-owned company gained consent from the Tararua District Council for 53 wind turbines on the Puketoi Range, 40km south of Dannevirke, though that has been appealed.

MRP also has consents for 60 turbines at its proposed Turitea wind farm, about 10km southeast of Palmerston North along a 14km ridge in the northern Tararua Range.

Last month, Contact Energy dumped plans to build a giant wind farm on the Waikato coast and has put another windfarm, Waitahora near Dannevirke, on ice. Contact said the cost of building wind turbines was about $20 a unit dearer than geothermal power projects, which cost $70 to $80 a unit.

Meanwhile, MRP's Ngatamariki will take the company's geothermal production to 40 per cent of its total generation, though it came on stream a month late.

The plant came in slightly under budget and power production is better than expected. Output is 4 per cent or 3MW better than expected, which Heffernan said would be positive for the station's economics and cashflow.